Various tools have been known in the past for working with cements, concretes, mastics and/or muds to, for example, prepare, apply and finish a desired shape or smooth surface for various building surfaces. For example, some tools used for preparing the surface of, for example, concrete, include trowels. Another example are various tools used to prepare and finish, for example, mastics and mud for drywall, including, flat boxes, corner finishing boxes, corner finishing tools, and automatic taper (taping) machines. Some examples of various previously known corner finishing tools may be found in U.S. Pat. Nos. 2,824,443; 5,419,693; 5,423,666; 5,622,729; 6,155,809; and 7,114,869: among others. In any case, regardless of type, these tools are often hand tools that are used to apply substances to and/or smooth various building surfaces, such as walls, ceilings and floors, and often result in skilled craftsman working on a number of surfaces for long periods of time during the work day. As such, the weight of the tool, ease of use, and quality of quick results may contribute to its appeal to the skilled craftsman.
For many of these tools, one aspect of improving their usefulness during the working day includes a quick yet high integrity attachment, retaining, and releasing system, so that the tool can be utilized both with injected mud as an applying tool, and without injected mud, as a spreading tool. Similarly, a corner finishing tool may be used with, or without, a corner finisher applicator box. Proper functioning of the tool includes how it glides along the surfaces, for example, a corner joint of drywall. The mechanical durability is also an important aspect of various designs for such tools. One particular example of an attachment system, is the ball style attachment, retention, and releasing system for a corner finisher applicator and finishing tool 100, that is illustrated in FIG. 1
Referring to FIG. 1, in this illustration the ball end 115 of a corner finisher applicator box 110 is snapped into socket 125 of the finishing tool 120 and retained or held in place by a retention clip or spring 105A, 105B. The applicator box 110 can be attached to the corner finishing tool 120 so as to provide mud or mastic from the applicator box 110 through the corner finisher tool 120 to, for example, a corner interface of two wall portions or a ceiling and wall of drywall sheets. Removal or disengagement of the tools is often needed during use of the tools, and in this case requires pulling the finisher tool 120 off of the applicator box 110. However, these attachment, retaining, and releasing systems or mechanization are known to fatigue the retention clip or spring 105A, 105B during use, resulting in tools which fall off during use and need to be repaired frequently by, for example, replacement of the retention clip or spring 105A, 105B.
FIGS. 2, 3A, & 3B show some other known attachment, retaining, and releasing systems used with corner finisher tools and corner applicator boxes. In these examples, various types of attachment, retaining, and releasing mechanism are employed to attach, retain, and release a corner finisher tool 220 (e.g., 120 in FIG. 1) to either an applicator box (not shown in FIG. 2 or 3; 110 in FIG. 1), or handle end 215 (not shown in FIG. 1 or 3). Referring to FIG. 2 a corner finishing tool and handle tool setup 200 is provided, including an attachment, retaining, and releasing system including levers 230A & 230B. In operation, levers 230A & 230B are rotated inwardly against a spring force applied by spring 222. In doing so, relief cuts in shafts 235A and 235B are rotated into an open position (moved outward) allowing the ball end 215 of handle 210 to be removed from the corner finishing tool 220 through the enlarged opening 225, thereby releasing it from the handle 210. When released, levers 230A & 230B are allowed to return to an orientation where the attachment ball 215 is either locked out of the tool or locked into the corner finishing tool 220 by shafts 235A and 235B.
Referring now to FIGS. 3A and 3B, a further example of a prior art attachment, retaining, and releasing system for attachment of a ball end fits into a socket section 310, 315 of either a handle or corner applicator box is accomplished by the sliding of a sheet metal interlocking piece 305 with and engaging and disengaging slot 325. This action is done against a biasing spring 307. In this system, as in the above system, the retaining and releasing mechanism (sliding sheet metal interlocking piece 305) is held in position by a biasing spring 307 and requires user motion to release the retaining and releasing mechanism for either engaging or disengaging a corner by using a tab 330 attached to the sliding sheet metal interlocking piece 305. For example, FIG. 3B shows the sliding sheet metal interlocking piece 305 in its releasing position wherein the biasing spring 307 is compressed and the wider opening portion 320A of the sliding sheet metal interlocking piece 305 is located around the socket section 310, 315. This position is achieved by a user pushing on tab 330. In this position, the ball end of a corner applicator box of handle (that is smaller than the large opening 320A) is insert through the large opening 320A and fit into the socket section 310, 315. FIG. 3A on the other hand, shows the sliding sheet metal interlocking piece 305 in its retaining position wherein the biasing spring 307 is expanded and the narrow opening portion 320B is located around the socket section 310, 315. In this position, a ball end (of a larger diameter than the socket section 310, 315 and the narrow opening portion 320B) of either a handle or corner applicator box may have been placed in the socket section 310, 315 and thereby be retained therein during use of the corner finishing tool.
However, these prior art embodiments have problems associated with high cost to produce and/or sharp edges which have been known to cut into the geometry of the ball end (e.g., 115 and 215) thereby shortening the life of the tools. In addition, all these prior art attachment, retaining, and releasing systems require additional effort by the user to actuate, for both attachment and release of the finishing tool to the applicator box or handle.
In another aspect of the prior art, these corner finisher tools operate in a manner such that the tools are moved along a corner of a room under construction while applying and or spreading “mud” or “mastic” materials intended to fill gaps and/or smooth the surface finish. The finished surface of the “mud” or “mastic” is made smooth by the wiping action of the “blades” in the finishing tool. One example of prior art for these corner finisher tool blades can be seen in FIG. 4.
Generally, there are two types of blades in the known corner finisher tools. The main or working blades 420A and 420B are primarily responsible for leaving a nice finish in the mud as it flows out of the central region of the tool 405A and 405B and under the working blades 420A and 420B. These blades have an angled surface at one end 425A and 425B allowing the 2 blades to come together to form a point which relates to and defines the inner most geometry of the ‘corner’ of the wall and/or wall to ceiling interface. A second set of blades, running or width control blades 440A and 440B, are mounted in the tool frame 410A and 410B at right angles to the working blades 420A and 420B. These running or width control blades 440A and 440B control the width of the applied mud and glide along the wall and/or ceiling surface during use, ideally allowing little to no mud to pass under them. These blades are typically shorter than the working blades and have both ends squared off at 90 degree angles from their longitudinal sides (not pointed). Corner finisher tool sizes typically vary from 2″ to 4″ wide. For these size tools the running or width control blades are typically 2.5″ long, regardless of the tool size. The larger tools allow for a greater width of mud in each corner making blending of corner imperfections easier. However, motion of the tool along the corner can become less smooth especially as tool size increases, partially due to the shorter length of the running or width control blades relative to the working blades 420A and 420B. Some prior art corner finisher tools have included the added complexity of wheels in various locations to improve the tools motion along the corner. However, these wheals and related parts are know to increase the problems with tool cleaning, get stuck during operation, and wear out quickly in the abrasive “mud” or ‘mastic” environment.